Java tutorial
/* * ClueWeb Tools: Hadoop tools for manipulating ClueWeb collections * * Licensed under the Apache License, Version 2.0 (the "License"); you * may not use this file except in compliance with the License. You may * obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or * implied. See the License for the specific language governing * permissions and limitations under the License. */ package io.bfscan.clueweb12; import java.io.IOException; import java.util.Arrays; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.apache.log4j.Logger; import tl.lin.data.pair.PairOfIntLong; public class MergeTermStatistics extends Configured implements Tool { private static final Logger LOG = Logger.getLogger(MergeTermStatistics.class); private static final String HADOOP_DF_MIN_OPTION = "df.min"; private static final String HADOOP_DF_MAX_OPTION = "df.max"; private static final int MIN_DF_DEFAULT = 100; // Throw away terms with df less than this. private static class MyCombiner extends Reducer<Text, PairOfIntLong, Text, PairOfIntLong> { private static final PairOfIntLong output = new PairOfIntLong(); @Override public void reduce(Text key, Iterable<PairOfIntLong> values, Context context) throws IOException, InterruptedException { int df = 0; long cf = 0; for (PairOfIntLong pair : values) { df += pair.getLeftElement(); cf += pair.getRightElement(); } output.set(df, cf); context.write(key, output); } } private static class MyReducer extends Reducer<Text, PairOfIntLong, Text, PairOfIntLong> { private static final PairOfIntLong output = new PairOfIntLong(); private int dfMin, dfMax; @Override public void setup(Reducer<Text, PairOfIntLong, Text, PairOfIntLong>.Context context) { dfMin = context.getConfiguration().getInt(HADOOP_DF_MIN_OPTION, MIN_DF_DEFAULT); dfMax = context.getConfiguration().getInt(HADOOP_DF_MAX_OPTION, Integer.MAX_VALUE); LOG.info("dfMin = " + dfMin); } @Override public void reduce(Text key, Iterable<PairOfIntLong> values, Context context) throws IOException, InterruptedException { int df = 0; long cf = 0; for (PairOfIntLong pair : values) { df += pair.getLeftElement(); cf += pair.getRightElement(); } if (df < dfMin || df > dfMax) { return; } output.set(df, cf); context.write(key, output); } } public static final String INPUT_OPTION = "input"; public static final String OUTPUT_OPTION = "output"; public static final String DF_MIN_OPTION = "dfMin"; /** * Runs this tool. */ @SuppressWarnings("static-access") public int run(String[] args) throws Exception { Options options = new Options(); options.addOption( OptionBuilder.withArgName("path").hasArg().withDescription("input path").create(INPUT_OPTION)); options.addOption( OptionBuilder.withArgName("path").hasArg().withDescription("output path").create(OUTPUT_OPTION)); options.addOption( OptionBuilder.withArgName("num").hasArg().withDescription("minimum df").create(DF_MIN_OPTION)); CommandLine cmdline; CommandLineParser parser = new GnuParser(); try { cmdline = parser.parse(options, args); } catch (ParseException exp) { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp(this.getClass().getName(), options); ToolRunner.printGenericCommandUsage(System.out); System.err.println("Error parsing command line: " + exp.getMessage()); return -1; } if (!cmdline.hasOption(INPUT_OPTION) || !cmdline.hasOption(OUTPUT_OPTION)) { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp(this.getClass().getName(), options); ToolRunner.printGenericCommandUsage(System.out); return -1; } String input = cmdline.getOptionValue(INPUT_OPTION); String output = cmdline.getOptionValue(OUTPUT_OPTION); LOG.info("Tool name: " + MergeTermStatistics.class.getSimpleName()); LOG.info(" - input: " + input); LOG.info(" - output: " + output); Job job = new Job(getConf(), MergeTermStatistics.class.getSimpleName() + ":" + input); job.setJarByClass(MergeTermStatistics.class); job.setNumReduceTasks(100); if (cmdline.hasOption(DF_MIN_OPTION)) { int dfMin = Integer.parseInt(cmdline.getOptionValue(DF_MIN_OPTION)); LOG.info(" - dfMin: " + dfMin); job.getConfiguration().setInt(HADOOP_DF_MIN_OPTION, dfMin); } FileInputFormat.setInputPaths(job, input); FileOutputFormat.setOutputPath(job, new Path(output)); job.setInputFormatClass(SequenceFileInputFormat.class); job.setOutputFormatClass(SequenceFileOutputFormat.class); job.setMapOutputKeyClass(Text.class); job.setMapOutputValueClass(PairOfIntLong.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(PairOfIntLong.class); job.setCombinerClass(MyCombiner.class); job.setReducerClass(MyReducer.class); FileSystem.get(getConf()).delete(new Path(output), true); long startTime = System.currentTimeMillis(); job.waitForCompletion(true); LOG.info("Job Finished in " + (System.currentTimeMillis() - startTime) / 1000.0 + " seconds"); return 0; } /** * Dispatches command-line arguments to the tool via the <code>ToolRunner</code>. */ public static void main(String[] args) throws Exception { LOG.info("Running " + MergeTermStatistics.class.getCanonicalName() + " with args " + Arrays.toString(args)); ToolRunner.run(new MergeTermStatistics(), args); } }